D. M. Alfianti, H. T. Tjendani, and B. Witjaksana, “Analysis of Improving the Quality of Mass Transportation Services with the Buy the Service (BTS) Scheme Using the Importance Performance Analysis (IPA) Method: Case Study of BTS Route Gresik – Lamongan”, JWS, vol. 4, no. 2, pp. 173–185, Feb. 2025.